Bava Batra, Chapter Three, Mishnah Five
The mishnah which we will learn today continue to deal with establishing ownership by possession (chazakah), the subject of the entire third chapter. Our mishnah teach the types of activities which if done for three consecutive years without the protest of the owner of the land, house or courtyard or courtyard, may continue to be done afterwards, even if the owner were to protest. For instance if Reuven does a certain activity on Shimons property for three years and Shimon does not protest, he cannot do so at a later date.
1) What are usages which are effective in establishing title through possession and what are usages which are not effecting in establishing title through possession?
a) If a man put a beast in a courtyard, or an oven or stoves or mill-stones, or reared fowl [in a courtyard] or put his manure in a courtyard, this is not effective in establishing title through possession.
b) But if he built for his beast a partition ten hand-breadths high, so too for an oven, so too for a stove, so too for a mill-stone, [or] he brought fowl inside the house, or prepared for his manure a place three hand-breadths deep or three hand-breadths high, this is effective in establishing title through possession.
Our mishnah lists certain type of acts which if done on another persons property for three consecutive years, acquire automatic subsequent permission to continue to do the activity. In other words, after three years there is an assumption that the owner of the property does not mind the other person doing these activities, and he therefore loses his right to subsequently protest. In section 1a we learn that placing an animal or other object in anothers courtyard will not cause entitlement to do so. For instance if Reuven were to use Shimons courtyard for three years as a place for his animal and Shimon were not to protest, Shimon would still retain the right to protest later. In section 1b we learn that if Reuven had built a structure on the property of Shimon, and Shimon had not protested for three years, Shimon now loses the right to protest. We assume that if Reuven used the property for such a long time in such a substantial manner, than it is does not bother Shimon and he cannot later change his mind.